There are a number of situations where a power supply providing electrical energy to a device is only capable of producing low levels of power and/or low potential values. Typical weak power supplies having these characteristics comprise those using some type of energy harvesting from an external source, such as supplies which generate their electrical energy from ambient electromagnetic radiation or an ambient local temperature gradient. A typical achievable power of an energy harvesting power source is up to 1 W. If the external source varies, then the supply voltage generated, and/or the power delivered, may change. Such changes may affect the operation of the device being driven by the power supply.
Documents incorporated by reference in the present patent application are to be considered an integral part of the application except that to the extent any terms are defined in these incorporated documents in a manner that conflicts with the definitions made explicitly or implicitly in the present specification, only the definitions in the present specification should be considered.